The present invention relates to the field of writing instruments, and more particularly their assembly.
In the present context <<writing instrument>> means any instrument for manually tracing writing on an adapted surface. Examples of writing instruments are for example pencils, pens, ballpoint or felt-tipped pens, and even adapted styluses. All these writing instruments typically have an elongated form for gripping a front part of the writing instrument between the tips of the thumb and at least one of the index and middle fingers, while a rear part is supported in the grasping angle between the thumb and the index finger to stabilise the writing instrument in the hand.
Some of these ergonomic writing instruments comprise a front body and a rear body capable of turning, relative to the front body, relative to a longitudinal axis, for example to action an extension and retraction mechanism of a writing point.
However, a disadvantage of such writing instruments with a front body and a rear body rotating relative to each other is the difficulty of ensuring a reliable mechanical bond between the front body and the rear body, with connecting means for simple and easily industrialisable assembly. As the front body and the rear body will frequently turned relative to each other in both directions of rotation about the longitudinal axis throughout the shelf life of the writing instrument, a connection by screwing for example may not be suitable.